在单击提交按钮后使用PHP进行验证失败时，防止引导程序模式消失

Question

My question is how do I stop modal from closing, on two occasions, when user clicks the sign up button:

• if the inputs are invalid? and display PHP error message
• inputs are valid and to display PHP success message for couple of seconds before closing modal?

for the first case if I reopen the modal I can see the validation error messages which are displayed by PHP.

I have checked this similar question but haven't figure it out how to do it in my case yet so any help will be much appreciated. I would like to fully understand what is going on and what I am doing.

So far after reading here and there I noticed that this can probably be achieved by:

• JQuery / JavaScript to do the form validation and not to use PHP
• some people suggested using iframe

Is there a way to use the PHP code below and display error / success messages from this code? or it has to be done via JQuery/JS?

My PHP with HTML code

<?php 
ob_start();
include('header.php');
include_once("db files/db_connect.php");

if(isset($_SESSION['user_id'])) {
    header("Location: index.php");
}
$error = false;
if (isset($_POST['signup'])) {
    $name = mysqli_real_escape_string($conn, $_POST['name']);
    $email = mysqli_real_escape_string($conn, $_POST['email']);
    $password = mysqli_real_escape_string($conn, $_POST['password']);
    $cpassword = mysqli_real_escape_string($conn, $_POST['cpassword']); 
    if (!preg_match("/^[a-zA-Z ]+$/",$name)) {
        $error = true;
        $uname_error = "Name must contain only alphabets and space";
    }
    if(!filter_var($email,FILTER_VALIDATE_EMAIL)) {
        $error = true;
        $email_error = "Please Enter Valid Email ID";
    }
    if(strlen($password) < 6) {
        $error = true;
        $password_error = "Password must be minimum of 6 characters";
    }
    if($password != $cpassword) {
        $error = true;
        $cpassword_error = "Password and Confirm Password doesn't match";
    }

    if (!$error) {
        if(mysqli_query($conn, "INSERT INTO users(user, email, pass) VALUES('" . $name . "', '" . $email . "', '" . md5($password) . "')")) {
            $success_message = "Successfully Registered!";
        } else {
            $error_message = "Error in registering...Please try again later!";
        }
    }

}
?>



<!-- Modal -->
<div class="modal fade" id="myModal" tabindex="-1" role="dialog" aria-labelledby="registrationFormLabel" aria-hidden="true">
  <div class="modal-dialog modal-dialog-centered" role="document">
    <div class="modal-content" >
      <div class="modal-header">
        <h5 class="modal-title" id="registrationFormLabel">Register</h5>
        <button type="button" class="close" data-dismiss="modal" aria-label="Close">
          <span aria-hidden="true">&times;</span>
        </button>
      </div>
        <div class="modal-body">


<!-- REGISTRATION FORM -->
<div class="container">
<div class="form-row">
<div class="col">
    <form onsubmit="return validateForm()" role="form" action="<?php echo $_SERVER['PHP_SELF']; ?>" method="post" name="signupform">
        <fieldset>
            <legend>Sign Up</legend>
            <div class="form-group">
                <label for="name">Name</label>
                <input type="text" name="name" placeholder="Enter Full Name" required value="<?php if($error) echo $name; ?>" class="form-control" />
                <span class="text-danger"><?php if (isset($uname_error)) echo $uname_error; ?></span>
            </div>                  
            <div class="form-group">
                <label for="name">Email</label>
                <input type="text" name="email" placeholder="Email" required value="<?php if($error) echo $email; ?>" class="form-control" />
                <span class="text-danger"><?php if (isset($email_error)) echo $email_error; ?></span>
            </div>
            <div class="form-group">
                <label for="name">Password</label>
                <input type="password" name="password" placeholder="Password" required class="form-control" />
                <span class="text-danger"><?php if (isset($password_error)) echo $password_error; ?></span>
            </div>
            <div class="form-group">
                <label for="name">Confirm Password</label>
                <input type="password" name="cpassword" placeholder="Confirm Password" required class="form-control" />
                <span class="text-danger"><?php if (isset($cpassword_error)) echo $cpassword_error; ?></span>
            </div>
            <div class="form-group text-center">
                <input id="modalSubmit" type="submit" name="signup" value="Sign Up" class="btn btn-primary" formnovalidate />
            </div>
        </fieldset>
    </form>
    <span class="text-success"><?php if (isset($success_message)) { echo $success_message; } ?></span>
    <span class="text-danger"><?php if (isset($error_message)) { echo $error_message; } ?></span>
</div><!-- / col -->
</div><!-- / form-row -->

<!-- already registered row -->
<div class="row">
<div class="col text-center">   
    Already Registered? <a href="login.php">Login Here</a>
</div>
</div>  <!-- / already registered row -->
</div><!-- / REGISTRATION FORM container-->

        </div><!-- / Modal body div -->
      </div>
  </div>
</div><!-- / Modal -->

My modal opens when the user clicks the button on index page and here is the JQuery code

$(document).ready(function(){
    $("#myBtn").click(function(){
        $("#myModal").modal();
    });
}); 

Answer 1

Add below PHP script after end of document ( /html ) before script tag

<?php 
if ($error) {
    echo '<script>$("#myModal").modal("show");</script>';
} else {
    echo '<script>$("#myModal").modal("hide");</script>';
}
?>

Answer 2

Invalid: You can stop the submit button from submitting if the inputs are invalid.

To stop submit use the code

$(':input[type="submit"]').prop('disabled', true);

To show modal

$("#myModal").modal('show');

To enable submit again, when modal is closed due to error, use the code (You will want to enable it again so the user can try again)

$("#myModal").on('hidden.bs.modal', function (e) {
        $(':input[type="submit"]').prop('disabled', false);
    });

For the validation I would do it this way (add a success variable):

if (!$error) {
    if(mysqli_query($conn, "INSERT INTO users(user, email, pass) VALUES('" . $name . "', '" . $email . "', '" . md5($password) . "')")) {
        $success = 1;
    } else {
        $success = 2;
    }

And then call it like this:

<?php if($success == 1){ ?>
<script>
    $(document).ready(function() {
        $("#yoursuccessmodal").modal('show');
    });
</script> <?php } ?>

You can then choose to add a fade to it, or have the user click it away. The modal will then show AFTER the submition has been sent.

This better work, as I have used it this way in my project as well and it works like a charm for me.